The present invention relates to an organopolysiloxane composition.
Epoxy resin has been traditionally used as a molding material for light emitting diode (LED) elements. Epoxy resin has outstanding transmittance due to its high modulus of elasticity. However, various temperature conditions and temperature changes lead to the decline of lamp efficiency since the crystal structure collapses, cracks occur between the wire, chip, and epoxy resin, and disconnections occur occasionally between wire bondings. Moreover, epoxy resin has an unsatisfying physical property in the aspects of thermal resistance and light stability with brighter and shorter wavelengths. When a ray such as ultraviolet ray is transmitted to epoxy resin, the optical and chemical properties are damaged as the combination of organic polymer is destroyed. Accordingly, the molding material of epoxy resin turns yellow, affecting the color of the ray and decreasing the life span of the light emitting device.
It has been suggested to use silicone resin in order to solve the above problems. Compared to organic resin, not only is the thermal resistance and light stability of silicone better than those of epoxy resin, but it is transparent and not easily discolored or deteriorated physically. Thus, the use of silicone has been increasing in the field of light emitting diodes. Still, although silicone resin is outstanding in mechanical strength and chemical stability, it shows unsatisfactory physical property in the aspects of brightness, and therefore studies have continued to improve a higher brightness.
For example, Japanese Laid-open Patent Publication No. 2002-265787 discloses performing an additional curing of a particular organopolysiloxane with a phenyl group and an alkenyl group and a particular organohydrogenpolysiloxane with a phenyl group by using both the increase of siloxane crosslink and π-π interaction between aromatic rings in order to enhance the refractive index of the cured products. Also, there is a research for improving a gas barrier property of a molding material of a light emitting diode element.